skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application

Abstract

The development of high resolution, room temperature semiconductor radiation detectors requires the introduction of materials with increased carrier mobility-lifetime ({mu}{tau}) product, while having a band gap in the 1.4-2.2 eV range. AlSb is a promising material for this application. However, systematic improvements in the material quality are necessary to achieve an adequate {mu}{tau} product. We are using a combination of simulation and experiment to develop a fundamental understanding of the factors which affect detector material quality. First principles calculations are used to study the microscopic mechanisms of mobility degradation from point defects and to calculate the intrinsic limit of mobility from phonon scattering. We use density functional theory (DFT) to calculate the formation energies of native and impurity point defects, to determine their equilibrium concentrations as a function of temperature and charge state. Perturbation theory via the Born approximation is coupled with Boltzmann transport theory to calculate the contribution toward mobility degradation of each type of point defect, using DFT-computed carrier scattering rates. A comparison is made to measured carrier concentrations and mobilities from AlSb crystals grown in our lab. We find our predictions in good quantitative agreement with experiment, allowing optimized annealing conditions to be deduced. A major resultmore » is the determination of oxygen impurity as a severe mobility killer, despite the ability of oxygen to compensation dope AlSb and reduce the net carrier concentration. In this case, increased resistivity is not a good indicator of improved material performance, due to the concomitant sharp reduction in {mu}{tau}.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
921754
Report Number(s):
UCRL-PROC-233251
Journal ID: ISSN 0277-786X; TRN: US0800809
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Journal Volume: 6706; Conference: Presented at: Hard X-Ray and Gamma-Ray Detector Physics VIII, San Diego, CA, United States, Aug 26 - Aug 30, 2007
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANNEALING; BORN APPROXIMATION; CHARGE STATES; EV RANGE; FUNCTIONALS; OXYGEN; PERTURBATION THEORY; PHONONS; PHYSICS; POINT DEFECTS; RADIATION DETECTION; RADIATION DETECTORS; RESOLUTION; SCATTERING; SIMULATION; TRANSPORT THEORY

Citation Formats

Lordi, V, Aberg, D, Erhart, P, and Wu, K J. First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application. United States: N. p., 2007. Web. doi:10.1117/12.739117.
Lordi, V, Aberg, D, Erhart, P, & Wu, K J. First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application. United States. https://doi.org/10.1117/12.739117
Lordi, V, Aberg, D, Erhart, P, and Wu, K J. Mon . "First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application". United States. https://doi.org/10.1117/12.739117. https://www.osti.gov/servlets/purl/921754.
@article{osti_921754,
title = {First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application},
author = {Lordi, V and Aberg, D and Erhart, P and Wu, K J},
abstractNote = {The development of high resolution, room temperature semiconductor radiation detectors requires the introduction of materials with increased carrier mobility-lifetime ({mu}{tau}) product, while having a band gap in the 1.4-2.2 eV range. AlSb is a promising material for this application. However, systematic improvements in the material quality are necessary to achieve an adequate {mu}{tau} product. We are using a combination of simulation and experiment to develop a fundamental understanding of the factors which affect detector material quality. First principles calculations are used to study the microscopic mechanisms of mobility degradation from point defects and to calculate the intrinsic limit of mobility from phonon scattering. We use density functional theory (DFT) to calculate the formation energies of native and impurity point defects, to determine their equilibrium concentrations as a function of temperature and charge state. Perturbation theory via the Born approximation is coupled with Boltzmann transport theory to calculate the contribution toward mobility degradation of each type of point defect, using DFT-computed carrier scattering rates. A comparison is made to measured carrier concentrations and mobilities from AlSb crystals grown in our lab. We find our predictions in good quantitative agreement with experiment, allowing optimized annealing conditions to be deduced. A major result is the determination of oxygen impurity as a severe mobility killer, despite the ability of oxygen to compensation dope AlSb and reduce the net carrier concentration. In this case, increased resistivity is not a good indicator of improved material performance, due to the concomitant sharp reduction in {mu}{tau}.},
doi = {10.1117/12.739117},
url = {https://www.osti.gov/biblio/921754}, journal = {},
issn = {0277-786X},
number = ,
volume = 6706,
place = {United States},
year = {2007},
month = {7}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: